The use of mobile devices in Long Term Evolution (LTE) based networks has continued to grow at a rapid pace. In turn, the volume of data traffic carried by network operators continues to rise. This combined with the demand for greater data rates has led to a need for increased radio resources. However, the radio spectrum is a finite resource and the cost associated with building, expanding and operating cellular networks is high such that efficient allocation of existing radio resources is playing a bigger part in scheduling of radio resources. Thus, network operators must pursue ways to exploit wireless networks by efficiently sharing resources.
There are several existing solutions for allocating radio resources. A relatively simple way to share radio resources is to assign each network operator a fixed set of Physical Resources Blocks (PRBs) such that each network operator's traffic is scheduled only within its dedicated PRBs. For example, two network operators are allocated a fixed set of PRBs such that there is complete physical isolation between network operators, i.e., the traffic load of one network operator does not change the traffic load of the other network operator. However, this solution provides poor overall spectral efficiency because it unnecessarily limits the instantaneous peak data rate available to users of one operator when there is low traffic in the cell from other network operators for a certain period of time. In other words, PRBs dedicated to a network operator having low traffic may go unused during a transmission time interval (TTI) while another network operator may not have enough PRBs to service its users during the TTI. Therefore, the throughput of a network operator is unnecessarily limited even when the load of the other network operator is low.
Another existing solution involves reserving a minimum fixed set of PRBs for each operator, and allowing one network operator to use more resources from the shared PRBs when other network operators have low traffic. However, this existing solution does not fully utilize all the available resources and lacks flexibility in resource allocation. For example, the minimum fixed set of PRBs dedicated to a network operator having low traffic may go unused during a TTI. Further, this existing solution increases the complexity of the scheduler as the scheduler always has to service each network operator every TTI.